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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Senior Software Engineer - **Company:** Mastercard - **Location:** O'Fallon, MO, United States - **Experience:** Expert - **Salary:** $115,000.0 - $184,000.0 - **Contract:** Permanent contract - **Skills:** Query Performance, Java (Programming Language), Cyber Security, Databases, Software Debugging, Middleware, PostgreSQL, Oracle (Applications), Commercial Software, Software Engineering, Spring-boot, ISO 8583, Splunk, Dynatrace - **Published:** September 8, 2026 - **Apply:** https://mastercard.wd1.myworkdayjobs.com/CorporateCareers/job/OFallon-Missouri/Senior-Software-Engineer_R-274320 ## About the Role * Strong software engineering experience writing applications using Java Spring Boot framework * Strong experience debugging performance issues with APM tools (i.e. Dynatrace, Splunk, Jprofiler, and JMH) * Strong experience optimizing DB queries in PostgreSQL and Oracle * Experience with Payments industry preferred (i.e. ISO 8583 messaging, 4-party model, and payment applications) * Systematic problem-solving approach, coupled with strong communication skills and a sense of ownership and drive * Time/project management, workload prioritization, knowledge sharing and a passion to learn/take on challenges is a must * Self-motivated demonstrating strong organizational and listening skills; and very detail oriented with the ability to carry out assigned tasks with minimal supervision * Strong verbal and written communications skills * Appetite for change and pushing the boundaries of what can be done with automation. Be curious about new technology, infrastructure, and practices to scale our architecture and prepare for future growth * Willingness and ability to learn and take on challenging opportunities and to work as a member of matrix based diverse and geographically distributed project team ## Description This is an exciting opportunity for you to join Mastercard and contribute to improving the response time for new applications that support the Authorization payment network. This position is on the performance engineering team that partners with development teams on optimization and testing. We are looking for an experienced engineer that is passionate about performance with a constant focus on improving system quality., * Design, configure, and execute performance tests and drive resolution of failures * Create performance measurements such as requests per second, P95 and P99 response latency, query performance, concurrency, and system utilization * Dig into Java code, databases, middleware, and vendor software to identify performance bottlenecks and resolve them * Improve the performance environment with your own code, automation, and external tools * Apply technical ability to coach and develop junior engineers * Deliver department and external presentations sharing results with stakeholders, All activities involving access to Mastercard assets, information, and networks comes with an inherent risk to the organization and, therefore, it is expected that every person working for, or on behalf of, Mastercard is responsible for information security and must: * Abide by Mastercard's security policies and practices; * Ensure the confidentiality and integrity of the information being accessed; * Report any suspected information security violation or breach, and * Complete all periodic mandatory security trainings in accordance with Mastercard's guidelines. ## Related Videos - [Our journey with Spring Boot in a microservice architecture](https://www.wearedevelopers.com/videos/511-our-journey-with-spring-boot-in-a-microservice-architecture) - [Kubernetes and Microservices with Multi-Model Databases](https://www.wearedevelopers.com/videos/382-kubernetes-and-microservices-with-multi-model-databases) - [Migrating half a million users to a new payment service provider](https://www.wearedevelopers.com/videos/730-migrating-half-a-million-users-to-a-new-payment-service-provider) - [Next Level Enterprise Architecture: Modular, Flexible, Scalable, Multichannel and AI-Ready?](https://www.wearedevelopers.com/videos/1017-next-level-enterprise-architecture-modular-flexible-scalable-multichannel-and-ai-ready) - [Fault Tolerance and Consistency at Scale: Harnessing the Power of Distributed SQL Databases](https://www.wearedevelopers.com/videos/1146-fault-tolerance-and-consistency-at-scale-harnessing-the-power-of-distributed-sql-databases) - [Branch your database like your code: How schema changes and pull requests go hand in hand](https://www.wearedevelopers.com/videos/350-branch-your-database-like-your-code-how-schema-changes-and-pull-requests-go-hand-in-hand) ## Related Articles - [Highest Paying Tech Companies for Developers](https://www.wearedevelopers.com/magazine/220-highest-paying-tech-companies-for-developers) - [Why Upskilling And Reskilling is Important For Developers](https://www.wearedevelopers.com/magazine/428-why-upskilling-and-reskilling-is-important-for-developers) - [Highest Paying Tech Companies in Europe](https://www.wearedevelopers.com/magazine/162-highest-paying-tech-companies-in-europe) - [Top-Paying Tech Jobs (with Salaries)](https://www.wearedevelopers.com/magazine/372-top-paying-tech-jobs-with-salaries) - [What’s the Difference between a Junior, Mid, and Senior Developer?](https://www.wearedevelopers.com/magazine/238-what-s-the-difference-between-a-junior-mid-and-senior-developer) - [Best Countries for Software Engineers](https://www.wearedevelopers.com/magazine/267-best-countries-for-software-engineers)